Chest
Volume 103, Issue 1, January 1993, Pages 151-157
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Clinical Investigations
Trends in Physician-Diagnosed Asthma Prevalence in Manitoba between 1980 and 1990

https://doi.org/10.1378/chest.103.1.151Get rights and content

We attempted to assess recent changes in the prevalence of physician-diagnosed asthma and the possible influence of diagnostic exchange on these trends. The routinely collected data of the provincial Health Insurance Plan (physicians' claims) were used to determine the annual prevalence of physician-diagnosed asthma in Manitoba. Results indicate that the prevalence of physician-diagnosed asthma increased for all age groups in both male and female subjects between 1980 and 1990. The average increases were the highest in the age group 5 to 14 years for both sexes. The average increases varied with age and there were significant differences between the two sexes. There was evidence of increasing diagnostic exchange, that is, a tendency to label patients with asthma instead of alternative diagnoses. This was particularly prominent in those younger than 35 years of age. However, the increased prevalence of physician-diagnosed asthma, even for the younger population, cannot be fully explained by diagnostic exchange.

Section snippets

METHODS AND MATERIALS

The provincial Health Insurance Plan is administered by the Manitoba Health Services Commission (MHSC) that also maintains a registry of the total population of Manitoba classified by age and sex. Virtually all health services used by approximately 1,100,000 Manitobans both within and outside the province are recorded and paid for by the MHSC. Physicians' claims for payment indicate the reason for using health services, ie, the diagnoses. A single diagnosis is recorded on each physician claim

RESULTS

Table 1 shows that, in Manitoba, the number of people seen and treated for asthma approximately doubled during the 1980s. In 1989, 14,281 male subjects and 14,497 female subjects (256 and 254 per 10,000, respectively), were seen for asthma in comparison with 7,659 male subjects (140 per 10,000) and 6,899 female subjects (125 per 10,000) in 1980. The age distribution was bimodal for both sexes. The highest age-specific physician-diagnosed prevalence was found for male children 5 to 9 years old.

DISCUSSION

Data reported in this study clearly show that the prevalence of physician-diagnosed asthma increased in Manitoba during the 1980s for all age groups and both sexes. These increases varied with age and were the highest in children. There were significant differences between the two sexes: increases were greater in male children and female adults.

Our results are consistent with the prevalence of physician-diagnosed asthma in children in the United States,14 who showed similar prevalence increases

ACKNOWLEDGMENT

We thank Manitoba Health Services Commission for permission to use their data and advice during the preparation of this report.

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    Supported by a grant from MRC Canada, the Manitoba Centre for Health Policy and Evaluation, the Canadian Institute for Advanced Research, and a Career Scientist Award (No. 6607–1314–48) from Health and Welfare, Canada, to Dr. L. L. Roos.

    Manuscript received January 27; revision accepted Mar 8.

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